7,404 research outputs found
Ca impurity in small mixed He-He clusters
The structure of small mixed helium clusters doped with one calcium atom has
been determined within the diffusion Monte Carlo framework. The results show
that the calcium atom sits at the He-He interface. This is in agreement
with previous studies, both experimental and theoretical, performed for large
clusters. A comparison between the results obtained for the largest cluster we
have considered for each isotope shows a clear tendency of the Ca atom to
reside in a deep dimple at the surface of the cluster for He clusters, and
to become fully solvated for He clusters. We have calculated the absorption
spectrum of Ca around the transition and have found that
it is blue-shifted from that of the free-atom transition by an amount that
depends on the size and composition of the cluster.Comment: 24 pages, 11 figures. Accepted on Journal of Chemical Physic
mRNA COVID-19 vaccine is well tolerated in patients with cutaneous and systemic mastocytosis with mast cell activation symptoms and anaphylaxis
Mastocytosis encompasses a heterogeneous group of diseases characterized by the presence of clonal mast cells (MCs) in tissues and symptoms of MC activation, including anaphylaxis.1
Vaccination has been shown to cause exacerbation of MC mediator-related symptoms.2
Vaccines against coronavirus disease 2019 (COVID-19) are the solution to the current pandemic, but reports of anaphylaxis following vaccination with the BNT162b2 Pfizer-BioNTech mRNA vaccine have emerged.3
As such, it is important to provide evidence of the safety of mRNA vaccines in populations at risk for anaphylaxis, including patients with mastocytosis and MC activation symptoms
Information and Communication Technology (ICT) and International Business Travel: Mobility Allies?
Like forecasts about the paperless office, technological solutions to the problem of international business travel continue to be deferred. As with the increased use of office paper, international business travel is defying predictions of its decline. There is growing evidence to suggest that business sectors which seem ideally placed to substitute information and communication technology (ICT) for travel, are actually generating more physical travel than other sectors. This paper develops a case study of the Irish software industry to exemplify why international travel is not diminishing in importance how and the ICT and business travel relationship is changing in this sector. The paper presents research findings that suggest that a cycle of substitution, generation and modification relationships have occurred as mobility interdependencies have developed.Peer Reviewe
Social media, protest cultures and political subjectivities of the Arab spring
This article draws on phenomenological perspectives to present a case against resisting the objectification of cultures of protest and dissent. The generative, self-organizing properties of protest cultures, especially as mobilized through social media, are frequently argued to elude both authoritarian political structures and academic discourse, leading to new political subjectivities or âimaginariesâ. Stemming from a normative commitment not to over-determine such nascent subjectivities, this view has taken on a heightened resonance in relation to the recent popular uprisings in the Middle East and North Africa. The article argues that this view is based on an invalid assumption that authentic political subjectivities and cultures naturally emerge from an absence of constraint, whether political, journalistic or academic. The valorisation of amorphousness in protest cultures and social media enables affective and political projection, but overlooks politics in its institutional, professional and procedural forms
Biodigital publics: personal genomes as digital media artifacts
The recent proliferation of personal genomics and direct-to-consumer (DTC) genomics has attracted much attention and publicity. Concern around these developments has mainly focused on issues of biomedical regulation and hinged on questions of how people understand genomic information as biomedical and what meaning they make of it. However, this publicity amplifies genome sequences which are also made as internet
texts and, as such, they generate new reading publics. The practices around the generation, circulation and reading of genome scans do not just raise questions about biomedical regulation, they also provide the focus for an exploration of how contemporary public participation in genomics works. These issues around the public features of DTC genomic testing can be pursued through a close examination of the modes of one of the best known providersâ23andMe. In fact, genome sequences circulate as digital artefacts and, hence, people are addressed by them. They are read as texts, annotated and written about in browsers, blogs and wikis. This activity also yields content for media coverage which addresses an indefinite public in line with Michael Warnerâs conceptualisation of publics. Digital genomic texts promise empowerment, personalisation and community, but this promise may obscure the compliance and proscription associated with these forms. The kinds of interaction here
can be compared to those analysed by Andrew Barry. Direct-to-consumer genetics companies are part of a network providing an infrastructure for genomic reading publics and this network can be mapped and examined to demonstrate the ways in which this formation both exacerbates inequalities and offers possibilities for participation in biodigital culture
Esquemes argumentatius i coneixement cientĂfic. Un estudi sobre la comprensiĂł de la flotabilitat a diferents nivells educatius
Es presenta un estudi sobre les respostes escrites dâestudiants de diversos nivells educatius a una activitat presentada com una narrativa en forma de conte. LâanĂ lisi es basa en identificar arguments dels estudiants que sĂłn estudiats en base a teories dâargumentaciĂł. Lâestudi dels elements dels arguments ens permet inferir sobre les concepcions cientĂfiques i alternatives dels estudiants i trobar esquemes o patrons argumentatius comuns. La comparaciĂł entre nivells educatius ens mostra que els tipus dâarguments no varien gaire entre nivells educatius perĂČ sĂ que es troben diferencies quant al tipus dâexplicacions que poden ser animistes o que no tenir res a veure amb la fĂsica als nivells educatius mĂ©s baixos
Influence of differences between sample and mobile phase viscosities on the shape of chromatographic elution profiles
The injection of samples whose viscosities are appreciably different from Ăhat of the motile phase can result in highly distorted elution profiles, showing severai maxima. The distortions are produced at the rear of the band when the viscosity of the sample solvent is higher than that of the motile phase. It is shown that the distortion of the peaks produced on injecting arbutin in columns of aminopropyl silica, using water as mobile phase and mixtures of 2-propanol and water as the sample solvent, grows in importance when the sample size increases, when the viscosity of the sample solvent increases and when the flow rate is decreased On the other side distortions at the band front are observed when arbutin dissolved in water or in acetonitrile + water mixtures is injected in a 2-propanol-water (50:50) mobile phase of higher viscosity. These trends are coincident with the predictions of a hydrodynamic instability criterion postulated several years ago and up to now almost entirely ignored in chromatography, except in relation with size exclusiĂłn chromatography
Shifting new media: from content to consultancy, from heterarchy to hierarchy
This is a detailed case history of one of Londonâs iconic new media companies, AMX Studios. Some of the changes in this firm, we assume, are not untypical for other firms in this sector. Particularly we want to draw attention to two transformations. The first change in AMX and in Londonâs new media industry more generally refers to the field of industrial relations. What can be observed is a shift from a rather heterarchical towards a more hierarchical organized new media industry, a shift from short-term project networks to long-term client dependency. The second change refers to new media products and services. We want to argue for a shift from cool content production towards consultancy and interactive communications solutions
Activity coefficients of hydrocarbons at infinite dilution in di-n-octyltin dichloride: comparison with results obtained in other alkyltin solvents
The gas chromatographic method was employed to measure the infinite dilution activity coefficients of twenty-eight hydrocarbons of different types in di-n-octyltin dichloride between 323.15 and 353.15 K, and ofseven branched alkanes in tri-n-octyltin chloride between 313.15 and 333.15 K. A comparison is made between the results obtained for all the solutes in both solvents and in tetra-n-octyltin
Indymedia and the long story of rebellion against neoliberal capitalism
Indymedia was born of the anti-globalisation movement of the late 1990s and quickly spread to become a social movement in its own right. This article reflects on how prescient the claims of the anti-globalisation movement have proven to be and how 20âyears ago Indymedia and the anti-globalisation movement predicted there was trouble ahead and that neoliberalism was a central part of the problem. It notes how a history of struggle and protest emanating from the days of Indymedia has developed over time building a counter-politics that is becoming ever wiser about the multiple intersectional harms of capitalism and ever more sophisticated in its political response. The challenge is what comes next
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